A HISTORY OF SCIENCE 



frame no hypothesis ; for whatever is not deduced from 

 the phenomena is to be called an hypothesis; and 

 hypotheses, whether metaphysical or physical, whether 

 of occult qualities or mechanical, have no place in 

 experimental philosophy. . . . And to us it is enough 

 that gravity does really exist, and act according to the 

 laws which we have explained, and abundantly serves 

 to account for all the motions of the celestial bodies 

 and of our sea." 2 



The very magnitude of the importance of the theory 

 of universal gravitation made its general acceptance 

 a matter of considerable time after the actual dis- 

 covery. This opposition had of course been foreseen 

 by Newton, and, much as he dreaded controversy, he 

 was prepared to face it and combat it to the bitter 

 end. He knew that his theory was right ; it remained 

 for him to convince the world of its truth. He knew 

 that some of his contemporary philosophers would 

 accept it at once ; others would at first doubt, question, 

 and dispute, but finally accept; while still others 

 would doubt and dispute until the end of their days. 

 This had been the history of other great discoveries; 

 and this will probably be the history of most great 

 discoveries for all time. But in this case the discoverer 

 lived to see his theory accepted by practically all the 

 great minds of his time. 



Delambre is authority for the following estimate of 

 Newton by Lagrange. "The celebrated Lagrange," 

 he says, "who frequently asserted that Newton was 

 the greatest genius that ever existed, used to add ' and 

 the most fortunate, for we cannot find more than once 



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